Field of Invention
Various embodiments relate generally to an electronic device and, more particularly, to a semiconductor memory device and an operating method thereof.
Description of Related Art
The demand for non-volatile memory devices that can be electrically programmed and erased without refresh operations for rewriting data at predetermined intervals is increasing.
Conventional non-volatile memory devices have multiple memory blocks located on a single plane. Recently, new technology has come about where memory blocks are stacked on multiple planes.
In a non-volatile memory device, a program operation writes data into memory cells, a read operation reads data stored in the memory cells, and an erase operation erases data from the memory cells.
A multi-level cell program method stores two or more bits of information in a single cell. In a single level cell program method, two different states that are distinguished by threshold voltages are generated. However, in the multi-level cell program method, the programming operation may be repeated to store two or more bits of information. In a multi-level cell program operation, a least significant bit (LSB) program operation and a most significant bit (MSB) program operation are generally performed.
Conventionally, when data is read from two planes at the same time, a read operation may be performed depending on whether an MSB program operation is performed on both of the planes. In other words, only when both of the planes are programmed using MSB or LSB program operations can the read operation be performed on two planes at the same time. The read operation may be performed when the two planes are in the same MSB program state. Therefore, conventionally, when two planes are in different program states, a read operation cannot be performed on both planes at the same time.